Fix previous commit, missed an include

Signed-off-by: falkTX <falktx@falktx.com>

distrho/src/DistrhoPluginVST2.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2022 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -17,6 +17,7 @@
 #include "DistrhoPluginInternal.hpp"
 #include "../DistrhoPluginUtils.hpp"
 #include "../extra/ScopedSafeLocale.hpp"
+#include "../extra/ScopedPointer.hpp"
 
 #if DISTRHO_PLUGIN_HAS_UI && ! DISTRHO_PLUGIN_HAS_EMBED_UI
 # undef DISTRHO_PLUGIN_HAS_UI